Tutorial That Separates Services

Question

I have a project I have been working on for awhile.  It currently is an Access database front end to a SQL database.

 

I would like to move the entire project to C# .Net Core.  I would like to completely separate the back end from any front end applications.  Eventually I would like to have an API that other people could use, a web app, and a few mobile applications that rely on the backend database.

 

I have been looking around for a good tutorial that shows how to seperate all projects.  I looked at the studend application from this site, but it looks like the model is duplicated.

 

Any help would be appreciated.